A House of Commons report found that cross-border commuters would be most impacted by any potential changes
The Taoiseach has said there is a 'possibility' of stricter border controls between Ireland and the UK if Britain chooses to leave the EU.
Enda Kenny, speaking to reporters while attending a GAA match in London, said a Brexit would be likely to 'adversely' affect Irish trade with Britain.
The Guardian reports that Mr Kenny said: "Whether there would be border controls or custom controls, these things are a possibility, but obviously they would require some very serious negotiations and my preference for the Irish electorate who have a significant part in this referendum is to vote to stay... for Britain to stay as a strong and central member of the European Union for the future".
Foreign Affairs Minister Charlie Flanagan told the Irish Times that he failed to see how any possible border restrictions "will not become a live issue if there is a vote to leave".
In a report published last week, the House of Commons Northern Ireland Affairs Committee explained that, in the event of a Brexit, "the border between Northern Ireland and the Republic would become an external border for the EU and so would principally be a matter of negotiation between the UK and EU. The scope of any post-Brexit trade deal would have an influence on the nature of the border".
The committee found that the group most impacted by any 'hard border' would be those who "regularly cross between the two for work, leisure or study". They were told there could now be as many as 30,000 cross-border commuters.
The report highlights concerns that a softer border in Ireland could become a 'back door' for people to evade UK border controls. However, it also highlights PSNI concerns over practical difficulties in imposing stricter border controls given the number of crossings.
It has also been suggested that stricter controls could be implemented between the island of Ireland and mainland Britain to overcome some of the potential difficulties.
The report concludes: "In the event of a Brexit, an arrangement that maintains a soft land border between Northern Ireland and the Republic but which does not see restrictions imposed on travel within the UK would need to be a priority".
The referendum on Britain's membership of the EU takes place on June 23rd.